.net - Eventhandler for serial port data receiving work only in debug mode -

it's quite strange. eventhandlers serial port seem working in debug mode. problem is, @ hardware side, rx , tx pins connected, means share same data line. in case, there 2 datareceived events triggered after every send. first 1 command itself, , second answer need. here code part:

private sub mspserialport_datareceived(byval sender object, _                                        byval e serialdatareceivedeventargs) _                                  handles mspserialport.datareceived     'handles serial data received events     dim inum integer = mspserialport.bytestoread     updateformdelegate1 = new updateformdelegate(addressof updatedisplay)      if inum > 0         redim mbreceivebuffer(inum - 1)         mspserialport.read(mbreceivebuffer, 0, inum)          if inum > 1             me.invoke(updateformdelegate1)         end if     end if  end sub 

the if-condition "inum > 1" intended neglect first received byte, command itself. works fine in debug mode, once program run in normal mode, received bytes in second event won't displayed. updatedisplay function shown below:

private sub updatedisplay()     'display received data     msreceivebufferstring = ""     = 0 ubound(mbreceivebuffer)         msreceivebufferstring &= (mbreceivebuffer(i).tostring("x2") & " ")     next      select case mbtestidflag         case gbtest_id_02      'sw-id             txtswid.text = msreceivebufferstring         case gbtest_id_2f      'trim value             txttrim.text = msreceivebufferstring         case else             'do nothing     end select  end sub 

does have ideas why doesn't work? because of delegate function, or eventhandler, or sth else? many in advance!